Isolated spin qubits in SiC with a high-fidelity infrared spin-to-photon interface

TL;DR

This paper demonstrates a high-fidelity spin-to-photon interface using divacancies in SiC, highlighting their potential for quantum communication due to long coherence times and optical addressability.

Contribution

It presents the first demonstration of high-fidelity spin-to-photon conversion in isolated divacancies in epitaxial SiC films, with insights into their optical and spin coherence properties.

Findings

Divacancies in 4H-SiC exhibit minimal spin-mixing.

Optical linewidths are comparable to those in recent entanglement experiments.

3C-SiC divacancies have millisecond Hahn-echo coherence times.

Abstract

The divacancies in SiC are a family of paramagnetic defects that show promise for quantum communication technologies due to their long-lived electron spin coherence and their optical addressability at near-telecom wavelengths. Nonetheless, a mechanism for high-fidelity spin-to-photon conversion, which is a crucial prerequisite for such technologies, has not yet been demonstrated. Here we demonstrate a high-fidelity spin-to-photon interface in isolated divacancies in epitaxial films of 3C-SiC and 4H-SiC. Our data show that divacancies in 4H-SiC have minimal undesirable spin-mixing, and that the optical linewidths in our current sample are already similar to those of recent remote entanglement demonstrations in other systems. Moreover, we find that 3C-SiC divacancies have millisecond Hahn-echo spin coherence time, which is among the longest measured in a naturally isotopic solid. The presence of defects with these properties in a commercial semiconductor that can be heteroepitaxially grown as a thin film on shows promise for future quantum networks based on SiC defects.